new wording for error message in T199055, T374571.
I went down a rabbit hole reducing a test case. registered a new WP account so I could be sure I had clean user prefs.
Some cases where a user is actually violating policy may be obvious what the message is complaining about. Less clear if they didn't violate any policy at all. We should fix the message so it's clear for everyone that encounters it what the purpose of the CSP restriction is. maybe a reference to phabricator?